I bought some friends for my clown loach. 3 2" clown loaches and all was well but I have noticed that they have developed tiny little pinhead 'holes/craters'. They look like someone has cut out a very shallow pinhead sized circle , its primarily on the top fin although they do have a few in other parts of the body. its easy to see on the top fin as the black is gone to reveal the orange underneath. One loach appears worse than the others with one of its 'holes' getting to rice bubble size on the top fin (though sttill shallow).
I have very good eyes and a have got a good look at the problem. There are no parisites visible, no infection at the site. At first I thought it could be ich but none of the telltale signs of ich are there (white spots). I dont think its injury, too circular and too evenly spread amoungst the fish. Fish themselves do not yet appear ill, their colour is good and appetite is fine.
Water conditions are good PH neutral, nitrates have been low to very low for the past few weeks and I have been being doing a lot of water changes hoping to avoid the new loaches getting ill. Temperature has been high (~30C) due to Australian summer temperatures being crazy hot night and day. Also have previously done 2 teatments of prazi anti parisite treatment as directed on the bottle (because everyone says they come full of worms).
As a side note. My big loach (3 to 4 times their size) hates his new friends
he hides in his log and if they come near him he chases them away. His colour is also faded, poor guy. I guess I should have let him live alone. Any ideas? Im just going to have to try a broad spectrum antibiotic if I cant diagnose.
edit:
The symptoms do not seem to match anything on this list as the holes are just holes with no swelling, blisters or borders.
